Technical Interview Question on Puzzles – The Ultimate Balance Puzzle

The Ultimate Balance Puzzle

There are 12 balls, one of which is different in weight (can be heavier or lighter)Find the odd ball using less than 3 weightings of the balance

The Solution FlowChart

Assume that the balls are identified as b1, b2, … b12. If we determine that a ball is normal, it will be relabeled ‘N’. If we suspect that a ball could potentially be heavier, let’s add a superscript ‘h’ to its label. If we suspect that a ball could potentially be lighter than normal, let’s add a superscript ‘l’ to its label.